In general, a mobile body such as a person or an object is tracked using the correlation between positional information of a mobile body and its identification. That is, it is possible to univocally identify and track a mobile body by way of the correlation between positional information of a mobile body and its identification. Various technologies have been developed with respect to mobile body tracking techniques (see Patent Document 1, Patent Document 2).
Patent Document 1 discloses a person tracking device which shoots images of persons in a surveillance area with a sensor (a viewable camera) so as to extract features of persons based on video signals output from the sensor. This person tracking device learns the correlation between identifications and features of persons, thus specifying an ID of a person based on the result of learning and newly extracted features. Additionally, the person tracking device outputs tracking information including an ID of a specified person and features of the person. When it fails to track a person halfway, the person tracking device specifies an ID of a person again based on the result of learning and the features of the person with whom tracking is resumed. That is, when an interruption occurs in tracking a person, the person tracking device specifies an ID of a person again based on the features extracted at the timing of resuming tracking.
Patent Document 2 discloses a mobile body tracking system equipped with a surveillance camera for shooting images in a predetermined space. This mobile body tracking system obtains positional information by identifying a mobile body based on the output of a surveillance camera, thus managing the correlation between positional information and a first identification inherent in each mobile body. Additionally, the mobile body tracking system reads a second identification inherent in each mobile body, thus managing the correlation between the positional information and the second identification. The mobile body tracking system includes a position management table for managing the correlation between positional information and a third identification. Moreover, the mobile body tracking system includes a position estimation table for managing the correlation between the second identification and the third identification. The mobile body tracking system tracks a mobile body with reference to the position management table and the position estimation table. That is, the mobile body tracking system integrates detection information produced by a plurality of sensors, thus tracking a mobile body.